Method of drawing glass.



'7 'J. R. SPEER & G. H. HARVEY. 7

METHOD OF DRAWING GLASS.

APPLICATION FILED NOV.23, 1906.

PATENTED JIAAN.V.15, 1907.

is not stretche JAMES RAMSEY SPEER, or PITTSBURQAND GhoRGn-iitjHA-RvEY, or

GLEN FIELD, PENNSYLVANIA.

ASSIGNORS TO BROWN S ViLLE GLASS COMPANY, OF PITTSBURG, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF' DRAWING GLASS.

Specification of Letters Patent. I

Patented Jan. 15, 1907.

' Application filed November 23,1906. Serial No. 344,708.

To all whom it may concern.-

Be it known that we, JAMES RAMSEY SPEER, residing at Pittsburg, and GEORGE H. HARVEY, residing atGlenfield, in the county of Alle heny, State of Pennsylvania, citizens of the nited States, have invented or discovered new and useful Improvements in Methods of Drawing Glass, of which the following is a specification.

The object of our invention is to, draw from a body of molten'glass'sheets of inclosed or other forms and to initially thin the wall of the sheets as a art of the operation of severing the drawn sl ieets from thegbait or drawing-tool.

In drawing glass sheets from molten glass contained in a receptacle the speed of Withdrawal of; the film, usually determines the thickness of the sheet. If the bait is quickly withdrawn, the glass adhering thereto will be at a temperature approaching that of the glass in the receptacle, and the sheet stretches and draws thin before it has time to set or ;harden by the action of the surrounding atmosphere or ofartificial cooling means. By reducing the s eed ofiwithdrawal the sheet I so readily while cooling more rapidly, thus causin it to draw thicker.

The drawingwhic accompanies this s ecification showsin vertical section, part y in elevation, an apparatus by which our improved method may be practiced.

On the drawing, -1 represents a bait by which the glass cylinder 2 is being-drawn from the molten bath 30f lass in the pot 4.

5 is a furnace by which thepot may be suitably; heated.

' The ait 1 is secured in any desired mannor to the carriage 6, which is moved up. alon the column or standard 7 by means of the eed-screw 8, working in the nut 9, stationary in the carriage. The interior of. the

, cylinder is supplied with air by means of an trate o ening 10 in the top of the bait and-asuita le pipe 11, connected to said opening. The feed-screw may be driven from any suitable source of'power, as an electric motor, whose epeed may be quickly ificreased The screw might ave its s eed varied by any of the we[ -known varia. le-(ppedgears. j (Not neeessa yto be illusis wit erably the full size of the cylinder. k if we can crac o The carriage 6 is lowered by the screw 9 until the dependingend ofthe bait 1' enters the molten glass 3 in the pot 4. The direction of rotation of the screw 9 is then reversed, whereuelon the bait rises from the bath, carrying t erewith the sheet -2 of glass, substantially conforming to the contour of the de endingen'd of the bait. the ba t l idrawn the speed of thecarriage 1s initiallymade'faster than re uired to draw a sheet or' desired uniform t 'ckness. The faster speed causes the sheet of glass, to stretch and become thinned, as is perfectly obvious. This thinning (shown at 12) Wlll continue for only such a time as will form a line of weakness about the cylinder, so that the crackin off, which will take place along this line, wi lbe much facilitated without injug to the body of the cylinder. y our method We ma dispense with the drawin ofthe usual me and shoulders on the cylinders, as we begin the drawing pref- Bythinningthe glass as describe the glass without checkin or cracking. the

body of the cylinder, which is apt to follow if the thinning is omitted.

By the Word initially usedin the description and claim We do not necessarily mean that the glass shall be thinned at the very instant the drawing is commenced, but that the thinning takes place at or about the beginning of the drawing operation, so

that the thinned circumferential line shall be close to the drawing-tool. What We claim is The method of drawingjheehglass, which consists in maintaining a 'gher temperature in an initial portion of the sheet by a-speed of withdrawal above the normal required to draw the-remainder of the sheet, whereby said initial portion is drawn thinner than the remaining portion.

Signed at Pittsburg, 12th day of November, 1906.

' JAMES RAMSEY srnna GEORGE HARVEY.

Witnesses A ELVA STANIEK,

O. E. Eoosns.

Pennsylvania, this 

